Hustler Turf Blog

June 2019, Admin

Why Your Lawn Mower Is Losing Power

One day you're mowing just fine, and the next your lawn mower is losing power for no apparent reason. It's a problem most of us have faced at one time or another. It can be a head-scratcher, but the solution might be simpler than you think. Follow these troubleshooting steps to determine the cause of a lawn mower losing power.

Why Is My Lawn Mower Losing Power?

Small engines, like the one in your lawn mower, are relatively simple and, for the most part, reliable. They are designed to run at a uniform speed that will provide the right amount of power to perform a certain task – like cutting grass. But every now and then something can occur that causes your engine to lose power. Your engine may stutter and stammer, or it may seem to gain and lose power repeatedly. It could also stop altogether, right in the middle of mowing.

Because small engines are relatively simple, the cause of a lawn mower losing power is often fairly straightforward. Your engine needs three things to operate: air, fuel and a spark. Usually, if you find your lawn mower losing power, the issue has something to do with one of these factors (or some combination of the three).

Troubleshooting a Lawn Mower Losing Power

Before you start troubleshooting your lawn mower, be sure to have a copy of your owner's manual handy. Your manual will provide important information about where to locate key components of the engine, as well as maintenance steps you should be taking. If you don't have your original owner's manual, you can find an online copy here.

Air Filter

Your lawn mower's air filter removes dirt and debris from the air before it is drawn into the carburetor. If it's doing its job, the air filter will become dirty and clogged over time which can prevent the fuel system from getting enough air. This can cause the engine to lose power. Start by checking the air filter, and clean or replace it if necessary. Air filters may need to be changed more often if you mow frequently, or under unusually dirty or dusty conditions.


Fuel degrades over time, often in as little as 30 days. Generally, the more ethanol there is in your gas the more quickly it will go bad. Ethanol attracts moisture and you will essentially end up with water in your gas if it sits around for too long. This is a common cause of a lawn mower losing power. Try draining the gas tank and replacing the fuel. In the future, you can add fuel stabilizer to your gas to make it last longer.

Fuel Filter

Much like the air filter, your engine's fuel system has a fuel filter that removes dirt from the fuel before it enters the carburetor. Much like the air filter, the fuel filter will get dirty over time, restricting the amount of fuel that can reach the engine and causing your mower to lose power. Take a look at the fuel filter and determine if it needs to be cleaned or replaced.

Oil Level

Like any engine, the right oil level is crucial to the operation of your lawn mower. The incorrect oil level – either too much or too little – can cause the engine to lose power. Too little oil and there won't be enough lubrication to reduce friction. Too much oil and you could end up with an oily froth that introduces air into the lubrication system. Check the oil level in your engine, and take note of the color and consistency to determine if it's time for an oil change.

Spark Plug

Even if your engine gets the perfect balance of fuel and air to run smoothly, it won't do any good if the spark plug doesn't provide the necessary spark. Spark plugs become pitted or fouled over time, causing inconsistent ignition. There may be fuel, carbon, dirt or oil on the spark plug electrodes that will cause an inconsistent spark and loss of power. It's generally a good idea to replace your lawn mower's spark plug once a year.

Heavy Use

lawn mower losing powerYour lawn mower is designed to operate under a wide variety of conditions, but it is also possible to put a strain on your engine. Cutting thick, overgrown grass and weeds can be a heavier load than your engine is used to and can cause it to lose power. If you're losing power while cutting thick grass, try raising the deck height. In many cases, mowing thicker grass, or more often than normal, can cause more grass clippings to build up under your deck, around the blade, and in the air filter. You may need to clean your mower more frequently.

Whether you're dealing with a lawn mower losing power or you're looking for a new machine, our team of lawn care experts is here to help. Contact us today to locate a Hustler retailer near you!